So, today was a great day. One of those rare one-in-a-million days that we actually have IMC conditions across the Imperial Valley. I was flying my wife, dogs and I from Phoenix to San Diego. For those that don't know the Imperial Valley, it's the Arizona/California desert, it's not known for any capacity to hold atmospheric moisture, and is generally severe-clear. Just about the time we crossed BZA the alternator quit. The idiot light illuminated, and the ammeter went to zero. We were at 8000 in IMC. I generally fly this flight a little higher but the headwinds were a factor, and the freezing level worked in tandem to keep us lower. ATC was solid professional. I advised my condition, and continued to troubleshoot/validate my issue while still flying the plane. All non-essential electrical devices were turned off to keep the battery draw as low as possible. Since going NORDO is a risk, we worked a clearance all the way to the IAF for the VOR-A approach to my intended airport, Brown Field (SDM). I use FlyQ for my charts/plates, and the iPad derives GPS data from my battery-operated hockey-puck GPS. I was advised that weather would improve suddenly once we crossed the mountains into the San Diego area, and could possibly take a visual. I said I'd rather have the VOR-A clearance, as it keeps me a little more procedural, and ATC agreed. As L.A. Center handed me to SoCal (San Diego), the controller said: "I know you're at risk for going NORDO. If this happens, just know I'm watching you closely and I'll keep everyone out of your way while you fly the approach." Then later he said, "I've called ahead to Brown, and you're already cleared to land Rwy 26R." The VOR-A approach was run in weather that had, as was told to me, improved to VFR conditions. The battery held for the remaining hour of flight time, so the alternator failure was really a non-event. Just enough of a thing to make the butt pucker a little. Being IMC at the time added to the fun. I don't know if anyone from Yuma, L.A., or SoCal ATC reads these threads or not, but if you do, I want to thank you and the team for your professionalism and your service! I also want to thank every flight instructor that I've had since ever, for making this event one that was handled with confidence, knowledge and a cautious respect for the situation. SO, for the Monday-morning quarterbacks: No, I didn't choose another airport. I continued onward. ATC was good with it, we coordinated many steps ahead so my NORDO risk would be close to a non-event. I was happy to make it all the way to SDM. It's my second-home-airport, and has full service facilities, and also had my truck parked and waiting for us. It sure beat landing in Yuma, being hundreds of miles from home, on a weekend.